(a) Field of the Invention
This invention relates to methods and devices for obtaining a three-dimensional digital representation of the teeth of a patient, and then using the system for creating the three-dimensional model to generate a model of the movement of the mandible the individual relative to the maxilla by using scans of movements of the mandible to establish a condylar axis that is then used to create a virtual, digital, articulator model of the patient's teeth.
(b) Discussion of Known Art
Mechanical dental articulators have been widely used in dentistry for over a century. As in U.S. Pat. No. 582,731 to Fourt, these early devices focused on creating a mechanical device that simulated the cooperation of the human mandible and maxilla. However, the use of these early devices led to recognition of great range in anatomical variation of patients, and of the complexity of the movement of the jaw as enabled by the temporomandibular joint (TMJ). Another example of an articulator is disclosed in U.S. Pat. No. 5,957,688 to Van Valey, incorporated herein by reference.
Broadly speaking, the TMJ encompasses the condyles of the jaw, which allow rotation about a condylar axis. Importantly, the TMJ not only enables rotation but also allows translation of the condyles of the jaw. Ligaments and muscles connect the jaw to the temporal bone and favor the resting position of the jaw and condyles. This anatomical arrangement allows the jaw to achieve pure rotation about condylar axis when the condyles are nested over their respective fossae, as well as translation from the fossae with the aid of the muscles and ligaments.
Mechanical articulators simulate the coupling of a patient's jaw by combining mechanical components that can be adjusted to simulate the jaw movement of a particular patient. Proper occlusion between the upper and lower jaws of a patient is essential to maximize comfort of the patient during mastication. Additionally, proper occlusion is essential for alleviating symptoms of patients suffering from tempormandibular joint syndrome. Because such occlusion of the upper and lower jaws is so closely related to condylar movement about the tempormandibular joint, a complete understanding of the movement of the patient's lower jaw about a hinge axis defined by the patient's condyles.
While a dominant factor of occlusal and candylar motion includes pivotal movement of the lower jaw about a hinge axis through the TMJ, other factors such as a patient's unique anatomical characteristics also affect the movement of the jaw. Accordingly, it has been quite difficult to not only record a comprehensive range of mandibular movement, but also precisely replicate this movement with precision through the use of mechanical dental articulators.
For decades, computerized systems have been adapted for modeling mandibular movements. These systems have the ability to create accurate three-dimensional models of a patient's teeth. An example of such a system is disclosed in U.S. Pat. No. 5,905,658 to Baba, and incorporated herein by reference in its entirety, and yet nother example is found in U.S. Pat. No. 7,824,346 to Marshall, incorporated herein by reference in its entirety. While computerized systems do provide advantages in their ability to manipulate large amounts of data describing the details of a patient's anatomy, it has been recognized that despite the accuracy in creating digital images of teeth, these systems still require the verification of the correctness of the resulting products through the use of an articulator, such as the Van Valey articulator mentioned above. See also, U.S. Pat. No. 8,374,714 to Dunne et al., incorporated herein by reference in its entirety, which includes a discussion of the prior art and recognition of the burdens of the unsatisfactory level in the amount of errors in prosthetics made using conventional methods. Still further, U.S. Pat. No. 6,152,731 to Jordan et al., incorporated herein by reference in its entirety, also discusses computerized methods for creating dental prostheses and for creating a virtual articulator. However, the Jordan et al. system is limited in that it relies on a model that uses vertical axial motion, instead of motion based on the actual articulation of the patient's jaw.
It can be appreciated that correction of prostheses ultimately leads to increase costs and discomfort to the patient. Accordingly, there remains a need for a system that reduces or minimizes errors in dental prosthetics.
Additionally, a review of the prior art reveals that data relating to, or describing, the actual geometry of a patient's teeth has not been used in a manner that allows the use of data collected using existing systems to be used in a manner that eliminates errors in prosthetics made with the use of this data.
A review of known devices and system reveals that there remains a need for a system that minimizes the need to use dental articulators and re-work or correct prosthesis made from data collected with digital systems.